Written by:
Vice President, Clinical Development, Vaccines & Immune Therapies, AstraZeneca
Head of Virology and Vaccine Discovery, Early Vaccines and Immune Therapies, AstraZeneca
The ever-evolving infectious disease landscape requires researchers to move quickly to adapt and develop solutions to prevent people from experiencing severe outcomes of disease. At AstraZeneca, we are exploring innovative technologies to maximise the potential of vaccines – with the goal of protecting as many people as possible from the burden of noncommunicable diseases.
The immune system: Our first line of defence against invaders
Our immune system’s job is to keep us healthy and protect us from diseases such as those caused by outside invaders like viruses and bacteria. When an invading pathogen such as a virus enters the body of someone with a healthy immune system, that person’s immune system recognises, attacks and destroys the virus. The immune system’s response against such a pathogen can be “remembered” by the immune system so that the next time the same person is exposed to the same virus, the immune response is stronger, faster and more effective.1
Vaccines help to keep us healthy because they “prime” the immune system by teaching our bodies how to respond to a pathogen before it can cause disease. When a person who has received a vaccine for a specific pathogen is then exposed to said pathogen, the immune system will quickly mount an attack to prevent the infection from taking hold and spreading. In effect, vaccines imitate natural infection without causing illness.2 Millions of lives are saved by vaccines each year.
Current vaccines rely on weakened, inactivated or purified parts of a pathogens to stimulate an immune response.2 However, there is an opportunity to create vaccines that can help protect us against more diseases by generating a durable immune response or an improved immune response in populations that have weaker immune systems like older adults and those with other comorbidities such as chronic respiratory or cardiovascular diseases.
What are virus-like particles?
A virus-like particle, or VLP, is a type of vaccine that mimics how naturally occurring viruses appear to our bodies. VLPs assemble to mimic the structure of a real virus but are not infectious and therefore do not cause disease. VLPs are made up of a central component that acts as a scaffold and numerous antigen-specific components. When combined, these components self-assemble to form the familiar shape of a natural virus as they appear to our immune system. This may prompt a stronger, more durable and possibly broader immune response from the body.
Discover more about how we are advancing vaccine development with VLPs
While current VLP vaccines effectively protect against several different diseases, including hepatitis B, human papillomavirus infection and malaria, the use of the VLP approach in other vaccines has been limited due to challenges with stability, difficulty in manufacturing, high production costs and sensitivity to temperature.3
The next generation of VLP vaccine technology
We are exploring the use of breakthrough computational methods to solve how to construct and manufacture VLPs resembling complex viruses. Our cutting-edge approach to VLPs may allow us to predict how viral proteins behave and fold into specific shapes. These individual viral proteins can be expressed and purified using new mRNA technology or traditional recombinant technologies and, when mixed, spontaneously self-assemble into a VLP, which can be the same size and shape as a real virus. Moreover, while the central scaffold components in our VLPs remain the same, the antigen-specific components can be tailored to resemble various viruses.
VLPs can have one antigen target per VLP (protecting against one specific virus), or they can have multiple different antigens on a single VLP (protecting against different viruses in combination).
Expanding the benefits of VLPs
By mimicking a virus so closely, our VLPs vaccines have the potential to improve upon existing vaccine technology. With intentionally designed VLPs, our aim is to produce better vaccines that may result in a stronger and more durable immune response to reduce the frequency of booster shots and offer a greater degree of protection against related viral strains.
At AstraZeneca, we are leveraging our decades of experience in vaccine and antibody development to maximise the potential of cutting-edge VLP vaccines. Our goal is to develop next-generation vaccines that provide long-lasting immunity to as many people as possible, protecting them from the serious burdens of infectious diseases.
